This Guidance describes a two-phase approach for a fit-for-purpose method for the assessment of plant pest risk in the territory of the EU. Phase one consists of pest categorisation to determine whether the pest has the characteristics of a quarantine pest or those of a regulated non-quarantine pest for the area of the EU. Phase two consists of pest risk assessment, which may be requested by the risk managers following the pest categorisation results. This Guidance provides a template for pest categorisation and describes in detail the use of modelling and expert knowledge elicitation to conduct a pest risk assessment. The Guidance provides support and a framework for assessors to provide quantitative estimates, together with associated uncertainties, regarding the entry, establishment, spread and impact of plant pests in the EU. The Guidance allows the effectiveness of risk reducing options (RROs) to be quantitatively assessed as an integral part of the assessment framework. A list of RROs is provided. A two-tiered approach is proposed for the use of expert knowledge elicitation and modelling. Depending on data and resources available and the needs of risk managers, pest entry, establishment, spread and impact steps may be assessed directly, using weight of evidence and quantitative expert judgement (first tier), or they may be elaborated in substeps using quantitative models (second tier). An example of an application of the first tier approach is provided. Guidance is provided on how to derive models of appropriate complexity to conduct a second tier assessment. Each assessment is operationalised using Monte Carlo simulations that can compare scenarios for relevant factors, e.g. with or without RROs. This document provides guidance on how to compare scenarios to draw conclusions on the magnitude of pest risks and the effectiveness of RROs and on how to communicate assessment results.

Following a request from the European Commission, the EFSA Plant Health Panel updated its pest categorisation of Xylella fastidiosa, previously delivered as part of the pest risk assessment published in 2015. X. fastidiosa is a Gram‐negative bacterium, responsible for various plant diseases, including Pierce's disease, phony peach disease, citrus variegated chlorosis, olive quick decline syndrome, almond leaf scorch and various other leaf scorch diseases. The pathogen is endemic in the Americas and is present in Iran. In the EU, it is reported in southern Apulia in Italy, on the island of Corsica and in the Provence‐Alpes‐Côte d'Azur region in France, as well as in the Autonomous region of Madrid, the province of Alicante and the Balearic Islands in Spain. The reported status is ‘transient, under eradication’, except for the Balearic Islands, Corsica and southern of Apulia, where the status is ‘present with a restricted distribution, under containment’. The pathogen is regulated under Council Directive 2000/29/EC and through emergency measures under http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32015D0789 (as amended http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32017D2352). The pest could enter the EU via host plants for planting and via infectious insect vectors. The host range includes hundreds of host species listed in the EFSA host plant database. In the EU, host plants are widely distributed and climatic conditions are favourable for its establishment. X. fastidiosa can spread by movement of host plants for planting and infectious insect vectors. X. fastidiosa is known to cause severe direct damage to major crops including almonds, citrus, grapevines, olives, stone fruits and also forest trees, landscape and ornamental trees, with high impacts. The criteria assessed by the Panel for consideration as a potential Union quarantine pest are met (the pathogen is present in the EU, but it has a restricted distribution and is under official control). X. fastidiosa is not considered as a regulated non‐quarantine pest (RNQP) as the pathogen may spread also via insect vector transmission.

The European Commission requested EFSA to conduct a pest categorisation of Spodoptera frugiperda (Lepidoptera: Noctuidae) a pest with hosts in 27 plant families. Favoured hosts include maize, rice and sorghum (Poaceae). Hosts also include crops within the Brassicaceae, Cucurbitaceae, Solanaceae, Rutaceae and other families. S. frugiperda is a taxonomic entity with reliable methods for identification. It is regulated in the EU as a harmful organism whose introduction into the EU is banned. It is native to tropical and subtropical regions of the Americas and migrates to temperate regions in North and South America during the summer. Establishment in temperate areas is prevented by its inability to overwinter. S. frugiperda has been intercepted on plant produce entering the EU. Phytosanitary measures are available to impede entry via traded commodities. In 2016, S. frugiperda was reported damaging maize in Africa. Subsequent reports indicate that it continues to spread severely damaging maize and other crops. If S. frugiperda spreads into north Africa, the likelihood of adults migrating into the temperate EU increases. Within the scope and level of analysis appropriate for pest categorisation, the EFSA Plant Health Panel concludes that S. frugiperda could establish in a small area of the southern EU from where it is likely to enter more northern regions forming transient summer populations, particularly in maize growing regions where impacts on yield could occur. However, uncertainties regarding establishment remain. Considering the criteria within the remit of EFSA to assess as regards status as a potential Union quarantine pest (QP) or as a potential regulated non-quarantine pest (RNQP), S. frugiperda satisfies the criteria to be regarded a Union QP but does not meet the criteria of (i) occurring in the EU territory, and (ii) plants for planting being the principal means of spread, criteria required for RNQP status.

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a quantitative analysis of the risk posed by the Flavescence dor ee phytoplasma (FDp) in the EU territory. Three scenarios were analysed, one with current measures in place (scenario A0), one designed to improve grapevine propagation material phytosanitary status (scenario A1) and one with reinforced eradication and containment (scenario A2). The potential for entry is limited, FDp being almost non-existent outside the EU. FDp and its major vector, Scaphoideus titanus, have already established over large parts of the EU and have the potential to establish in a large fraction of the currently unaffected EU territory. With the current measures in place (A0), spread of FDp is predicted to continue with a progression of between a few and ca 20 newly infested NUTS 2 regions during the next 10 years, illustrating the limitations of the current control measures against spread. FDp spread is predicted to be roughly similar between scenarios A1 and A2, but more restricted than under scenario A0. However, even with reinforced control scenarios, stabilisation or reduction in the number of infested NUTS 2 regions has only relatively low probability. Under scenario A0, FDp has a 0.5-1% impact on the overall EU grapes and wine production, reflecting the effectiveness of the current control measures against impact. Under both scenarios A1 and A2, FDp impact is predicted to be reduced, by approximately one-third (A1) to two-thirds (A2) as compared to A0, but the associated uncertainties are large. The generalised use of hot water treatment for planting material produced in infected zones has the most important contribution to FDp impact reduction in scenario A1 and has high feasibility. Both increased eradication and containment measures contribute to impact reduction under scenario A2 but the overall feasibility is lower. This is an open access article under the terms of the Creative Commons Attribution-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited and no modifications or adaptations are made.The EFSA Journal is a publication of the European Food Safety Authority, an agency of the European Union. SummaryFollowing a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed an analysis of the risk to plant health posed by the Flavescence dor ee phytoplasma (FDp) in the European Union (EU) territory, with the evaluation of risk reduction options. The temporal scale of this assessment is a 10-year time horizon and three scenarios are analysed, one corresponding to the current situation, with all current official control measures in place (scenario A0) and two alternative scenarios, with either a reinforcement of the hot water treatment (HWT) control measure to improve the phytosanitary status of grapevine propagation material (scenario A1) or a reinforcement of eradication and containment measures (scenario A2).Concerning entry, the P...

The Panel on Plant Health performed a pest categorisation of Nacobbus aberrans (Nematoda: Pratylenchidae), the false root-knot nematode, for the EU. The nematode was originally described from the American continent. Due to differences in host range as well as molecular variability among populations, N. aberrans should be regarded as a species complex (N. aberrans sensu lato). All populations belonging to this species complex are pests of important host plants in the EU. N. aberrans had been detected indoors in the EU in the 1950s and 1960s but is no longer reported to be present in the EU. It is regulated by Council Directive 2000/29/EC, listed in Annex IAI as N. aberrans (Thorne) Thorne and Allen. Species within the N. aberrans complex are endoparasitic with migratory and sedentary stages. They are highly polyphagous attacking many plant species. They are also found in soil where they can survive dry conditions and freezing temperatures. Plants for planting and soil are potential pathways for this nematode. Climatic conditions in the EU are similar to those found in the countries where the pest is present. Hosts of the nematode from which high-yield losses have been reported include potato, sugar beet, tomato and beans. The nematode only moves short distances (around 1m) but may be spread with plants and soil moving activities. Measures are available to inhibit EU entry via potatoes and soil as such but not all host plants are covered by current legislation. Entry of the nematode with plants and soil attached to plants for planting that are not regulated is therefore possible. N. aberrans does satisfy all the criteria that are within the remit of EFSA to assess to be regarded as a Union quarantine pest.

EFSA was asked for a partial risk assessment of Spodoptera frugiperda for the territory of the EU focussing on the main pathways for entry, factors affecting establishment, risk reduction options and pest management. As a polyphagous pest, five commodity pathways were examined in detail. Aggregating across these and other pathways, we estimate that tens of thousands to over a million individual larvae could enter the EU annually on host commodities. Instigating risk reduction options on sweetcorn, a principal host, reduces entry on that pathway 100-fold. However, sweetcorn imports are a small proportion of all S. frugiperda host imports, several of which are already regulated and further regulation is estimated to reduce the median number entering over all pathways by approximately 10%. Low temperatures limit the area for establishment but small areas of Spain, Italy and Greece can provide climatic conditions suitable for establishment. If infested imported commodities are distributed across the EU in proportion to consumer population, a few hundreds to a few thousands of individuals would reach NUTS 2 regions within which suitable conditions for establishment exist. Although S. frugiperda is a known migrant, entry directly into the EU from extant populations in sub-Saharan Africa is judged not feasible. However, if S. frugiperda were to establish in North Africa, in the range of thousands to over two million adults could seasonally migrate into the southern EU. Entry into suitable NUTS2 areas via migration will be greater than via commercial trade but is contingent on the establishment of S. frugiperda in North Africa. The likelihood of entry of the pest via natural dispersal could only be mitigated via control of the pest in Africa. If S. frugiperda were to arrive and become a pest of maize in the EU, Integrated Pest Management (IPM) or broad spectrum insecticides currently used against existing pests could be applied.

The Panel on Plant Health performed a pest categorisation of the gall midge Aschistonyx eppoi Inouye (1964) (Diptera, Cecidomyiidae), for the EU. A. eppoi is a well-defined and distinguishable species, native to Japan and Korea, and recognised as a pest of Juniperus chinensis, although our knowledge is solely based on one unique publication. A. eppoi is absent from the EU, and is listed in Annex IIAI of Directive 2000/29/EC. Its host plants, Juniperus spp. are also listed in Annex III of Directive 2000/29/EC. Plants for planting and branches are considered as pathways for this pest. A. eppoi has been intercepted twice (1974; 1975) in the EU and has been eradicated. The pest is likely to affect bonsai plants of J. chinensis if it were to establish in the EU territory. However, as it is unknown whether A. eppoi would attack the Juniperus spp. that occur in the EU, its potential impact on the wild vegetation is also unknown. As the pest originates from areas with warm climates, impact outdoors would affect the southern parts of the EU. Cultural control (destruction of infested material) and chemical control are the major control methods. All criteria assessed by EFSA for consideration as a potential quarantine pest are met, although there are high uncertainties regarding impact. The species is presently absent from the EU, and thus the criteria for consideration as a potential regulated non-quarantine pest are not met.

In 2009 a new three year EU funded project (QBOL) started on DNA barcoding of important plant pests. An international consortium of 20 partners (universities, research institutes, and phytosanitary organizations) from around the world, coordinated by Plant Research International (Wageningen, the Netherlands), will collect DNA barcodes from many plant pathogenic quarantine organisms, store these sequences in a database accessible over the internet, develop a DNA bank and train end‐users. All these activities should help National Plant Protection Services in the correct identification and detection of plant pathogenic quarantine organisms.